Process for treating gasoline or the like



Patented Oct. 10, 1933 UNITED STATES PATENT OFFICE PROCESS FOR TREATINGGASOLINE OR THE LIKE No Drawing. Application November 11, 1929 SerialNo. 406,518

3 Claims.

This invention relates to stabilization of gasolines, and moreparticularly to the prevention of color formation and gum formingsubstances in gasoline, and also to prevent the reduction in 5 antiknockproperties of said gasolines on storage.

It has been observed that when gasolines are stored, particularlycracked gasolines, and especially under the influence of light andoxygen,

1 chemical changes occur which affect the color,

increase the gum formation, and reduce the antiknock properties. In somecases all of these changes occur simultaneously, while in others theyoccur independently or in pairs. Although the chemistry of these changesis not thoroughly understood, I have discovered that certain compoundsact as stabilizing or inhibiting agents and substantially prevent thisundesirable chemical change from occurring.

Generally speaking, cracked gasolines are composed of mixtures ofhydrocarbons, principal among which are the aromatic, unsaturated,naphthene, and parafiin hydrocarbons. While it has not been definitelyproven, it is believed that color and gum formation and reduction inantiknock properties upon storage involve changes in the unsaturatedcompounds, more particularly in the highly unsaturated compounds such asdiolefins, terpenes, and related compounds.

Oxidation products of the various hydrocarbons present in the gasolinesare apparently responsible also for the changes noted.

The formation of color in gasolines is undesirable mainly from amarketing viewpoint, for changes in color are usually accompanied by theformation of gum-like and polymer-like materials which aifect not onlythe sale of the gasoline when dispensed from visible bowls, but also theoperation of the motor owing to clogging of the gasoline feed lines,interference with the proper operation of the carburetor, and thesticking of valves in the motor. Gum formation is likewise objectionablefor the same reasons.

The gum content of a gasoline is measured by a test which involves thegum formation. The present test is stated in terms of milligrams of gumformed upon the evaporation of a specific volume of the gasoline, namely100 cc. The presence of oxygen during evaporation increases the gumformation, but as this condition is one which is present in the use ofthe gasoline, it has a bearing upon its performance in the motor. Theso-called gum content of the gasoline will also vary as a function ofthe material in which it is evaporated, for example, in the presence ofcopper, the resulting gum will be very much higher than in glass. Thesetests have a bearing upon the performance of the gasoline in the motorand its auxiliary feed system, and the beneficial effects of myinvention will be indicatfed by such tests as well as by actual motortes s.

The antiknock property of a gasoline is among its most important andvaluable characteristics. The higher the antiknock value or rating of agasoline, the more efficient it is as a motor fuel. Knocking in a motoris an index of inefiioient operation because energy which otherwisewould be utilized in the operation of the motor must be dissipated byrapid cooling, and unless this remedy is resorted to, a condition willbe set up where auto-ignition occurs, thus interfering with the normalfunctioning of the motor. It has been observed that the higher thecompression pressure or compression ratio of a motor, the greater thetendency for a given fuel to knock, and inasmuch as the efficiency of amotor increases with compression pressure and compression ratio, it isdesirable that a motor fuel possess sufliciently high antiknockproperties to avoid knocking. The present tendency is to increase thecompression pressure of motors in order to increase their efiiciency ormileage per gallon of fuel consumed so that antiknock fuels are at apremium.

The change in antiknock rating during storage of a motor fuel isparticularlyembarrassing inthat although the antiknock rating of a tankof motor fuel is established and found to be satisfactory, there is acomplete uncertainty 'as to its antiknock value at the time of sale. Theeconomic loss of restoring such gasolines to their original antiknockvalue can be realized from cases which have been observed where theantiknock value has dropped from approximately fifty percent benzolequivalent to zero percent over a period of several months standing.

I have discovered that when relatively small amounts, forexample, from atrace up to two percent, more or less, of the inhibiting or stabilizingagents which are the subject of this invention are added to a gasolinewhich shows a tendcncy to depreciate with respect to color, gum, andantiknock properties, that such gasolines will pratically retain theiroriginal condition. I have found that these inhibitors or stabilizersare effective in preventing or reversing the changes which take place asa result of storage, exposure to light, or oxidation naturally occurringor under accelerated conditions.

I have discovered that camphor and its related derivatives, such ascamphorphorone and camphoric acid and others when added to motor fuels,especially cracked gasoline, are capable of accomplishing thestabilizing and inhibiting effects above pointed out, more particularlywith respect to the stabilization of color and antiknock values, and inthe present invention I employ for the purposes set forth the compoundsnamed.

Certain of the above compounds may possess antiknock properties, but thepresent invention is to be distinguished from the mere addition ofantiknock compounds to motor fuels in that my treatment preventsdeterioration of the gasoline upon storage or removes undesirablecharacteristics which have formed during storage, particularly withrespect to color and antiknock depreciation. In my invention the amountof reagent employed is materially less than that required in motor fuelsto impart antiknock properties thereto.

As examples of the color stabilizing properties of camphor and itsrelated derivatives, I may cite the following:

Starting with a gasoline of 18 color, which on exposure to diffusedsunlight for several days dropped to 14, I have found that by theaddition of approximately 0.1% of camphor and some of its derivativesthat the resultant color under similar conditions of exposure is 19;actually showing an improvement in color with the stabilizer.

Similarly I have found that with certain gasolines showing a markedtendency to depreciate in antiknock value without the addition ofcamphor and its derivatives one can by the addition of approximately0.1% of camphor avoid such depreciation. As an example a crackedgasoline upon storage without the use of my reagents dropped inantiknock valueto zero benzol equivalent from a value of approximately35% benzol equivalent when stored for several months. Upon the additionof 0.1% camphor this depreciation in benzol equivalent or antiknockrating was prevented under similar conditions of storage. I have foundfurther that under accelerated conditions of depreciation in antiknockvalue, for example exposure of a cracked gasoline to the action ofoxygen at elevated temperatures, which ordinarily caused a very markeddepreciation in antiknock-value, that such depreciation would beprevented by the addition of small amounts of camphor.

Stabilization of gum formation was also observed, for example with agasoline showing a gum content of 15 milligrams by the copper dish test.No substantial increase in the gum formation was observed, after a longperiod of storage or exposure of the gasoline to which a small quantityof camphor or its derivatives was added.

It can be appreciated that the present inven tion is of prime importanceto the oil refining industry since it assures a stable product afterrefining, and at the same time avoids a large expenditure in bringingout the anti-knock properties of depreciated gasoline by the addition ofcostly antiknock dopes or hydrocarbons, for example benzol. Theseinhibitors are not to be confused with antiknock dopes because theamount added will impart practically no antiknock properties per se, butsimply acts to prevent the loss of antiknock and other desirableproperties of the gasoline.

The above examples are given by way of illustration only, and are not tobe construed as limitations upon the spirit and broad scope of theinvention.

I claim:

1. The process of reducing deterioration during storage of crackedgasoline having anti-knock properties which comprises adding to suchgasoline a compound selected from the group which consists of camphor,camphorphorone, and camphorio acid.

2. The process of reducing deterioration during storage of crackedgasoline having anti-knock properties which comprises adding camphor tothe cracked gasoline.

3. The process of reducing deterioration during storage of crackedgasoline having anti-knock properties which comprises addingapproximately 0.1% of camphor to the cracked gasoline.

JACQUE C. MORRELL.

